H-25 



RESEARCH PROGRAMMES 



area although it generally remains north in the more temperate latitudes. Nine species of smaJl 

 odontocetes inhabit Antarctic waters, including the Killer Whale Orcinus orca, which may be 

 important in predator-prey interactions within the ecosystem. Mackintosh (1965) gives a good 

 summary of the biology of large whales. Brownell (1974) reviews existing information on the 

 small cetacea, but our knowledge of these mammals is far from complete and they will not be 

 further considered here. 



In Table 2, data on both the initial and present stocks of large whales are presented. They 

 represent the concensus among whale biologists and the methods by which the figures were 

 reached are summarized by Mackintosh (1965), Laws (1977 and in press) and the annual reports 

 of the International WhaUng Commission. There is more uncertainty about the Minke Whale, 

 which is less migratory than the other species; its food consumption has been estimated by 

 assuming that on the average it feeds in the Antarctic for half the year. The table indicates that 

 the initial stocks of large whales, before exploitation began, probably consumed about 180 

 million tons of krill, 12 million tons of squid and 4.5 million tons offish. Their numerical 

 abundance is now reduced to about 38 per cent of the initial population, their biomass more so, 

 and they are estimated to consume substantially less than before; namely, 33 milUon tons of 

 kriU, 5 million tons of squid and about 1 million tons of fish, annually. In order to predict 

 future trends of abundance it will be necessary to monitor the stocks for many years. 



The biology of Antarctic whales foDows a basic pattern: intensive feeding in Antarctic 

 waters in the summer montlis when they store up an energy reserve in the form of blubber, 

 followed by an autumn migration northwards. They feed during the winter at no more 

 than a tenth of the summer rate and in spring they migrate southwards again to feed. It has 

 been estimated that their body weight increases by about 50 per cent during the period of 

 intensive feeding (the Sperm Whale to a lesser extent), and most of this is lost in the winter. 

 The transfer of material, by metabolism, and the loss due to deaths outside Antarctic waters 

 formerly totalled about 19 million tons and are now estimated to total only 3 million tons. 

 While this drop is probably insignificant in relation to the whole of the Southern Ocean it may 

 be locally important, particularly with regard to the source of nutrients in lower latitudes. 



The distribution of these whales follows a circumpolar zonation with the larger species 

 tending to penetrate into colder more southerly waters (the Minke Whale is an exception), and 

 larger individuals within species also occupying the more southerly part of a species' range. This 

 pattern results, together with other behavioural and morphological specializations, in a measure 

 of ecological separation, particularly in feeding methods. 



3. Birds. 



Sea birds, particularly the penguins, albatrosses and petrels, are conspicuous members of 

 the Antarctic and sub-Antarctic ecosystems. They constitute an integral part of the Antarctic 

 ecosystem and exploitation of other resources could have a significant impact upon their 

 populations and on the ecosystem as a whole. Their distribution in the Southern Ocean is zonal, 

 the principal limits being the Antarctic coastal zone, the northern pack ice edge, the Antarctic 

 Convergence and the sub-Tropical Convergence. Due to the circumpolar nature of these zones, 

 many species are circumpolar in distribution. Sea birds are represented in the breeding stocks 

 south of the sub-Tropical Convergence, in the islands and geographic areas delineated by Carrick 

 and Ingham (1967), by eight famiUes and 44 species (Watson and others, 1971; Barratt and 

 Mougin, 1974). 



Seven species of penguins {Spheniscidae) occur in the region; three of these are confined 

 largely within the hmits of the pack ice. They comprise about 87 per cent of the stocks of birds 

 (or 90 per cent of the biomass) in the Antarctic and 53 per cent of the stocks of birds (or 83 

 per cent of the biomass) in the sub-Antarctic. In terms of biomass the Adelie Penguins are by 

 far the most important birds in the pack ice. Penguins are quite easy to study at their breeding 

 sites and thus their breeding biology has become well known. A few populations of penguins 



